The present invention relates generally to quarter turn fasteners, and more particularly to a new and improved quarter turn fastener for clamping together a plurality of panels, plates, disks, or the like, wherein enhanced clamping loading is achieved, and wherein further, the quarter turn fastener can only be rotated in a first direction so as to be disposed its locked or engaged position or mode, the quarter turn fastener can only be rotated in the opposite direction so as to be disposed in its unlocked or released mode or position, and the quarter turn fastener cannot be rotated beyond 90xc2x0 in either the locking or unlocking direction such that when the fastener is desired to be disposed in its locked or engaged position or mode, it is not inadvertently disposed or moved to its unlocked or released position or mode.
Quarter turn fasteners are of course well known in the art for securing or clamping together a plurality of panels, plates, disks, and the like as a result of partial rotation of the fastener through means of an arcuate extent of, for example, 90xc2x0. The panels, plates, disks, or the like are conventionally clamped between a head member formed upon a first end portion of the fastener shank, and a protruding portion formed upon a second opposite end portion of the fastener shank. While such quarter turn fasteners have obviously been quite satisfactory and have been successfully employed by workmen in connection with innumerable fastening applications or operations, it is desired to improve the clamping loading and back-off resistance of such fasteners so as to effectively prevent disengagement of permanently installed fasteners under field use environmental conditions.
In addition, as is well known and as has been descrbied briefly hereinabove, such fasteners are conventionally installed at their locked position by rotating the same through means of an arcuate extent of 90xc2x0 with respect to the initial insertion position of the fastener with respect to the panels, plates, disks, or the like with which the fasteners are operably being used. However, in accordance with the construction and structure of such conventional quarter turn fasteners, the fasteners are not effectively prevented from being rotated further in the same installation rotational direction and may in fact be rotated further in the same installation rotational direction beyond the 90xc2x0 locked position whereby the fasteners may be inadvertently moved, in effect, back to their unlocked or released positions such that the panels, plates, disks, or the like, are not in fact reliably or safely secured or clamped together.
A need in the art therefore exists for a new and improved quarter turn fastener wherein enhanced clamping loading is achieved, and wherein further, the quarter turn fastener can only be rotated in a first direction so as to be disposed its locked or engaged position or mode, the quarter turn fastener can only be rotated in the opposite direction so as to be disposed in its unlocked or released mode or position, and the quarter turn fastener cannot be rotated beyond 90xc2x0 in either the locking or unlocking direction such that when the fastener is desired to be disposed in its locked or engaged position or mode, it is not inadvertently disposed or moved to its unlocked or released position or mode.
Accordingly, it is an object of the present invention to provide a new and improved quarter turn fastener.
Another object of the present invention is to provide a new and improved quarter turn fastener which effectively overcomes the various operational disadvantages and drawbacks characteristic of prior art or conventional quarter turn fasteners.
An additional object of the present invention is to provide a new and improved quarter turn fastener which comprises specific structure wherein enhanced clamping loading is able to be achieved in connection with those fasteners which are to be permanently installed within particular assemblies.
A further object of the present invention is to provide a new and improved quarter turn fastener wherein the quarter turn fastener can only be rotated in a first direction so as to be disposed its locked or engaged position or mode, the quarter turn fastener can only be rotated in the opposite direction so as to be disposed in its unlocked or released mode or position, and the quarter turn fastener cannot be rotated beyond 90xc2x0 in either one of the locking or unlocking directions such that when the fastener is desired to be disposed in its locked or engaged position or mode, it cannot inadvertently be disposed or moved to its unlocked or released position or mode.
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of a new and improved quarter turn fastener wherein in accordance with a first feature or characteristic of the fastener, which is to be used in connection with relatively permanent fastener installations wherein the fasteners are not periodically or cyclically installed and removed, the same comprises a shaft, a head portion fixed upon a first end portion of the shaft, and a blade member fixed upon a second opposite end portion of the shaft. Opposite corner portions or regions of the blade member are bent upwardly such that the pointed upturned corner portions of the blade member bitingly engage the underside surface of, for example, a metal panel, plate, disk, or the like such that proper clamping loading is achieved. In addition, the biting engagement of the corner portions of the blade member with respect to the undersurface portion of the panel, plate, disk, or the like, effectively prevents disengagement of the fastener from the clamped plate, panel, or disk assembly under normal environmental vibrational conditions attendant usage of the fastener assembly within, for example, motorized applications.
In accordance with a second predominant feature or characteristic of the quarter turn fastener of the present invention, the shaft of the fastener is provided with a cam or stop member which is adapted to interact with a predeterminedly configured aperture defined within one of the panel, plate, or disk members. When the quarter turn fastener is rotated 90xc2x0 from its unlocked or released state or position to the locked or engaged state or position, the cam or stop member not only effectively centers the shaft of the fastener with respect to the aperture defined within the panel, plate, or disk, but in addition, prevents further rotation of the quarter turn fastener beyond the 90xc2x0 rotation already performed. In this manner, the quarter turn fastener cannot be rotated further. As a result of such structure, the quarter turn fastener cannot inadvertently again attain the released or unlocked state or position.